There is provided improved laser sintering systems that increase the powder density and reduce anomalies of the powder layers that are sintered, that measure the laser power within the build chamber for automatic calibration during a build process, that deposit powder into the build chamber through a chute to minimize dusting, and that scrubs the air and cools the radiant heaters with recirculated scrubbed air. The improvements enable the laser sintering systems to make parts that are of higher and more consistent quality, precision, and strength, while enabling the user of the laser sintering systems to reuse greater proportions of previously used but unsintered powder.